In current implementation of pblk_put_line_back behaviour there are two cases which are not handled.
First one is the race condition with __pblk_map_invalidate in which function we check for line state, which might be closed, but still not added to any list and thus explode in list_move_tail. This is due to lack of locking both gc_lock and line lock in pblk_put_line_back current implementation. The second issue is that when we are in that function, line is not on any list and pblk_line_gc_list might hit the same gc group and thus not return any move_list. Then our line will stuck forever unassigned to any list. Simply resetting gc_list to none will fix that. Signed-off-by: Igor Konopko <[email protected]> --- drivers/lightnvm/pblk-gc.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/lightnvm/pblk-gc.c b/drivers/lightnvm/pblk-gc.c index 31fc1339faa8..511ed0d5333c 100644 --- a/drivers/lightnvm/pblk-gc.c +++ b/drivers/lightnvm/pblk-gc.c @@ -64,19 +64,23 @@ static void pblk_put_line_back(struct pblk *pblk, struct pblk_line *line) struct pblk_line_mgmt *l_mg = &pblk->l_mg; struct list_head *move_list; + spin_lock(&l_mg->gc_lock); spin_lock(&line->lock); WARN_ON(line->state != PBLK_LINESTATE_GC); line->state = PBLK_LINESTATE_CLOSED; trace_pblk_line_state(pblk_disk_name(pblk), line->id, line->state); + + /* We need to reset gc_group in order to ensure that + * pblk_line_gc_list will return proper move_list + * since right now current line is not on any of the + * gc lists. + */ + line->gc_group = PBLK_LINEGC_NONE; move_list = pblk_line_gc_list(pblk, line); spin_unlock(&line->lock); - - if (move_list) { - spin_lock(&l_mg->gc_lock); - list_add_tail(&line->list, move_list); - spin_unlock(&l_mg->gc_lock); - } + list_add_tail(&line->list, move_list); + spin_unlock(&l_mg->gc_lock); } static void pblk_gc_line_ws(struct work_struct *work) -- 2.17.1
